The Mathnawi of Jalaluddin Rumi

He (God) hath said, "Let them weep much." Give ear, that the bounty of the Creator may pour forth the milk.
The cloud's weeping and the sun's burning are the pillar of this world: twist these two strands (together).
If there were not the sun's heat and the cloud's tears, how would body (substance) and accident become big and thick?

❧140. How would these four seasons be flourishing unless this glow and weeping were the origin?
Since the burning (heat) of the sun and the weeping of the clouds in the world are keeping the world fresh and sweet,
Keep the sun of your intelligence burning, keep your eye glistening with tears like the cloud!
You must needs have a weeping eye, like the little child: do not eat the bread (of worldliness), for that bread takes away your water (spiritual excellence).
When the body is in leaf (well-furnished), on that account by day and night the bough, (which is) the soul, is shedding its leaves and is in autumn.

❧145. The leafage (flourishing state) of the body is the leaflessness (unprovidedness) of the soul. Be quick! You must let this (body) dwindle and that (soul) increase.
Lend unto God, give a loan of this leafage of the body, that in exchange a garden may grow in your heart.
Give a loan, diminish this food of your body, that there may appear the face (vision) of (that which) eye hath not seen.
When the body empties itself of dung, He (God) fills it with musk and glorious pearls.
He (such a person) gives this filth and gets purity (in return): his body enjoys (what is signified by the words) He will purify you.

❧150. The Devil frightens you, saying, "Hark and hark again! You will be sorry for this and will be saddened.
If you waste away your body in consequence of these idle whims, you will become very sorry and anxious.
Eat this, it is hot and good for your health; and drink that for your benefit and as a cure,
With the intention (of acting on the principle) that (since) this body is your riding-beast that to which it is accustomed is best for it.
Beware, do not alter your habit, else mischief will ensue and a hundred maladies will be produced in brain and heart."

❧155. Such menaces does the vile Devil employ, and he chants a hundred spells over the people.
He makes himself out to be a Galen (for skill) in medicine, that he may deceive your ailing soul.
"This," says he, "is of use to you against any sorrow and pain." He said the same thing to Adam about an ear of wheat.
He utters (hypocritical expressions such as) "Ah, ah" and "Alas," while he twists your lips with the farrier's barnacle,
As (the farrier twists) the lips of a horse when shoeing it, in order that he (the Devil) may cause an inferior (worthless) stone to appear as a ruby.

❧160. He takes hold of your ears as (though they were) the ears of a horse, pulling you towards greed and acquisition (of worldly goods).
He claps on your foot a shoe of perplexity, by the pain of which you are left incapable of (advancing on) the Way.
His shoe is that hesitation between the two works (of this world and of the world hereafter)—"Shall I do these or shall I do those?" Take heed!
Do that which is chosen by the Prophet, don't do that which (only) a madman or (foolish) boy ever did.
"Paradise is encompassed"—by what is it encompassed? By things disliked, from which there comes increase of the seed sown (for the future life).

❧165. He (the Devil) hath a hundred spells of cunning and deceit, which would entrap (any one), even if he is (strong and wily as) a great serpent.
He (the Devil) will bind him, though he be (swift and elusive as) running water; he will make a mock of him, though he be the most learned man of the time.